Rolling mill



T. RASTELLI ROLLING MILL July 30, 1968 2 Sheets-Sheet 1 Filed May l9, 1965 INVENTOR Te\esore Rasi'elh BY Dam Ma mm,

ATTORNEYS y 968 T. R ASTELLI 3,394,577

ROLLING MILL I Filed May 19, 1965 2 Sheets-Sheet 2 REEL DRWE

51 NJ 3 a 2 E g INVENTOR I! I Te\esove Rosi'dh ATTORNEYS United States Patent 3,394,577 ROLLING MILL Telesfore Rastelli, Cheshire, C0nn., assignor to Textron Inc., Providence, R.I., a corporation of Rhode Island Filed May 19, 1965, Ser. No. 457,035 4 Claims. (Cl. 72-242) ABSTRACT OF THE DISCLOSURE This disclosure relates to a cluster-type mill for cold working and reducing metal in which the work rolls are so arranged and supported that the distance between the axes of the work rolls is greater than the vertical distance between a horizontal plane in which material is fed to the bite of the rolls and the horizontal plane in which the material is taken from the rolls.

This invention relates to rolling mills and, more particularly, relates to rolling mills for operating upon very thin material, often referred to as foil.

In cold rolling very thin metallic material there is a tendency for the material to wrinkle or fold. This occurs due to thinness of the material, the small area of contact of the material between the bite of the work rolls and the tension exerted on the material. Also, with very thin materials any irregularities in the face of the work rol-ls will appear continuously along the length of the strip ma terial.

The present invention overcomes, or substantially eliminates, this tendency towards wrinkling and folding of very thin strip material being rolled through the provision of a new and improved mill wherein the working rolls are so constructed and arranged as to provide a smoothing effect on the material as it is rolled. The invention may be utilized in various type rolling mills which are arranged to roll foil. However, it is particularly adapted for use in cluster type mills and will be disclosed in such environment.

Accordingly, an object of this invention is to provide a new and improved rolling mill for very thin strip material.

Another object of this invention is to provide a new and improved rolling mill for metallic foil.

Another object of this invention is to provide a rolling mill for metallic foil material having a new and improved arrangement of the working rolls which eliminates or substantially reduces the tendency of thin foil being rolled to wrinkle or fold.

A further object of this invention is to provide a new and improved rolling mill of the cluster roll type having a new and improved work roll arrangement.

A still further object of this invention is to provide a new and improved method of rolling metallic foil so as to eliminate or substantially reduce the tendency for wrinkles, folds or other imperfections to be introduced in the material as it is rolled.

The features of the invention which are believed to be novel are set forth with particularity and definitely claimed in the concluding portion of this specification. The invention, however, both as to its organization and operation, together with further objects and advantages thereof, may best be appreciated by reference to the following detailed description taken in conjunction with the drawings, in which:

FIG. 1 is an elevation predominantly in half section showing a cluster type rolling mill embodying the invention;

3,394,577 Patented July 30, 1968 FIG. 2 is a schematic diagram of a mill embodying the invention showing the working rolls of the mill of FIG. 1, greatly enlarged for exemplary purposes.

FIG. 3 is a schematic diagram of the work rolls of the mil-1 of FIG. 1.

To illustrate a preferred embodiment of the invention a cluster type mill 10 comprising a housing or frame 11 defining a mill cavity 12 is illustrated. Those skilled in the art will recognize this arrangement as the well-known Sendzimir type mill. Housing 11 is supported on a base 13 on a suitable foundation and contains therein a pair of cooperating work rolls 14 and 15, and upper and lower sets of intermediate rolls, each set comprising rolls 16 and 17. The faces of the intermediate rolls extend across the work rolls and are in turn backed up by upper and lower sets of casters each comprising caster-s 18, 19, 20 and 21. The casters 18-21 are supported and positioned through the use of members 22-25 which are attached to the frame and extend across the mill cavity.

The structural details of the casters form no part of the present invention and need not be described in detail. Sufiice it to say that each caster comprises a plurality of roller elements 27 supported from an arcuate saddle 28 having a plurality of collars 29 extending perpendicularly therefrom. The roller elements of each caster extend across the length of the intermediate and work rolls. The arcuate saddles are seated against the housing 11 in cavity 12. The collars extend from each saddle and support a shaft 29a upon which the bearing elements are rotatively mounted. The members 22-25 position and support the saddles along their length in the cavity 12. The details of construction of the casters may be seen in the copending application of John E. Eckert, Ser. No. 251,588, filed Jan. 15, 1963, and assigned to the same assignee as the present invention.

The intermediate rolls, and particularly the upper intermediate rolls, are supported by means such as springs 30 (only one shown) at either end thereof. The springs 30 depend from the housing and engage a journal cap 31 which rotatably supports the journal ends of the intermediate rolls. The intermediate rolls otherwise rest in the recesses defined by and between adjacent casters, which recesses position the intermediate rolls. A driving torque may be applied to the intermediate rolls and in the particular mill shown, the driving torque is applied to intermediate rolls 17.

In operation, strip material 32 to be rolled is introduced into the mill 10 through a window 33, passes between the bite of work rolls 14 and 15 and exits through another window 34 in housing 11.

The strip material 32, as more clearly shown in FIG. 2, is drawn from a pay-off reel 36, over a guide or deflector roll 37, through the bite of working rolls 14 and 15, over a second guide roll 38 to a wind-up reel 39. As is well known to those skilled in the art, such a take-up reel is driven by a reel drive indicated in block form at 40 which regulates both the torque and speed of reel 39 along a constant horsepower torque-speed characteristic as the material on the roll builds up, and thereby maintains the tension T in the strip between the bite of the work rolls and the take-up reel 39 essentially constant. Reel 36 may be provided with a similar drive, indicated in block form at 41, which acts as a brake, or other suitable retarding means to prevent undesired pay-off and maintain the tension T in the strip between the bite of the working rolls and the pay-off reel. Guide rolls 37 and 38 are small free turning rolls which function to guide the strip material 32 into and out of housing 11 in a substantially horizontal direction through windows 33 and 34. Guide roll 37 guides the material to the work rolls in a first plane P (FIG. 3) and guide roll 38 guides the material from the work rolls in a second plane P which is essentially parallel to plane P but displaced therefrom.

It will be noted, as more clearly seen in FIG. 3, the axes A and B of the work rolls 14 and 15, respectively, reside in a plane C which forms an acute angle with plane D through the bite of the rolls 14 and 15. Plane D is essentially perpendicular to the general direction E of travel of the strip material. It will be further be seen then that the distance between the axes A and B along plane C is greater than the distance between the axes A and B as measured between the points A and B in the vertical plane D.

In accordance with the invention, the work rolls 14 and 15 are arranged to not only perform a cold rolling reducing operation on the strip material 32 as it passes through the roll bite defined thereby in plane C but also to enable a smoothing action to be exerted on the thin strip and prevent wrinkling or folding thereof. It is apparent that as the strip is pulled through the mill there is a force exerted thereon by the torque of reel 39 which maintains tension T in the strip. The force produced on the strip by work rolls 14 and 15, driven by the rolls 17, reacts with the retarding force of reel 36 to maintain ten sion T in the strip.

It may be noted that unlike conventional reduction mills, the stri material is in contact with the work rolls 14 and 15 along their peripheral portions defined by the angles G and H. Thus, as the strip moves along the surface of roll 14 from the bite to a point of tangency J it is in full surface contact with roll 14. Similarly, as the unreduced strip moves from the point of tangency K with roll 15 to the bite, it is in full surface contact with roll 15 for a peripheral difference defined by the angle H.

As the strip moves from point K to the roll bite the horizontal component of velocity of the strip decreases, with the absolute velocity of any point on the strip remaining constant. As the strip moves from the roll bite to the point J the horizontal component of velocity of the strip increases, with the absolute velocity of any point on the strip being constant. This change in the velocity components is due to the curvilinear path the strip follows over a portion of the peripheries of the work rolls. This creates a plurality of forces acting upon the strip both before it enters the roll bite and as it leaves the roll bite which prevents wrinkling of the strip.

The forces or stresses produced in the strip and on the strip are not merely due to the tension in the strip, but also the forces normal to the strip exerted thereon by the work rolls in reacting against the continuous change in direction of the strip between the points K and J.

Therefore, the strip exerts a radially inwardly directed force on the surfaces of the work roll due to its change in direction and, hence, change in angular acceleration and the rolls exert a reacting force normal to the strip. This reacting force is uniformly distributed over any given line of contact of the strip across the face of the work rolls between the points K and J, and produces an ironing or anti-wrinkling efifect on the strips, and prevents wrinkling or folding thereof.

Any given line on a section of the strip material is subjected to an increasing normal pressure from point K to the bite and then a decreasing normal pressure from the bite to point J, such pressures being uniform across the width of the strip material and the face of the working rolls contacted thereby.

These pressures, together with the tension in the strip, produce a force or stress in the strip parallel to its direction of travel which tend to iron the strip material over the faces of the work rolls and hold the material taut against the face of the work rolls and prevent any wrinkling or folding.

The disclosed mill is illustrated as a modified Sendzimir 1-2-3-4 cluster mill of the type illustrated in the aforementioned copending application. This invention may be embodied in an existing mill having four casters in each set, or may be constructed without the casters 18. The relative diameters of intermediate rolls 16 and 17 may be varied to determine the angle of plane C with the vertical.

It may thus be seen that the objects of the invention set forth as well as those made apparent in the preceding description are efiiciently attained. Inasmuch as other embodiments of the invention as well as modifications to the disclosed embodiment thereof may occur to those skilled in the art the appended claims are intended to cover all embodiments of the invention which do not depart from the spirit and scope thereof.

What is claimed is:

1. In combination in a mill for reducing the thickness of strip material, upper and lower sets of back-up roil means defining recesses between adjacent roll means, intermediate rolls in said recesses, upper and lower work rolls in recesses defined by said intermediate rolls, said intermediate rolls and said back-up roll means being so constructed and arranged that the axes of said work rolls reside in a plane which forms an acute angle with a plane normal to the direction of material introduced to said work rolls, and means for introducing material to said work rolls in a first horizontal plane and receiving material from said work rolls in a second horizontal plane while maintaining said material under tension.

2. A cluster mill for reducing the thickness of strip material including a housing, upper and lower sets of back-up rolls supported in said housing and defining recesses therebetween, said sets of back-up rolls having parallel axes which define a generally arcuate path, upper and lower intermediate rolls in said recesses, an upper and a lower work roll in recesses defined by said upper and lower intermediate rolls, the distance between the axes of said work rolls being greater than the vertical distance between the horizontal planes in which the axes of said work rolls reside, and means for introducing material to said work rolls in a first horizontal plane and receiving material from said work rolls in a second horizontal plane while maintaining said material under tension.

3. In a mill for reducing the thickness of strip material including a housing, upper and lower sets of back-up roll means supported in said housing and defining recesses therebetween, upper and lower sets of intermediate rolls in the recesses defined by said upper and lower backup rolls, a pair of work rolls in recesses defined by said sets of intermediate rolls, said intermediate and said backup rolls being so constructed and arranged that the axes of said work rolls reside in a plane which forms an acute angle with a plane normal to the direction of material introduced to said work rolls, means for introducing material to said work rolls in a first plane and receiving material from said work rolls in a second plane substantially parallel to said first plane while maintaining said material under tension.

4. A mill for reducing the thickness of strip material, comprising a housing having first and second apertures at opposite ends thereof for receiving and exiting strip material in essentially horizontal planes, upper and lower sets of back-up rolls in said housing defining recesses between adjacent rolls, intermediate rolls in said recesses, upper and lower work rolls in recesses defined by said intermediate rolls, the distance between the axes of said work rolls being greater than the vertical distance between the horizontal planes in which said axes reside, and means for introducing material to said work rolls through said first aperture in a first plane and receiving material from said work rolls in a second plane where said first and second planes are essentially parallel.

(References on fellowing page) Sendzimir. Spengler. Stone. Sendzimir. Lord.

6 3,078,909 2/ 1963 Maust. 3,147,648 9/ 1964 Sendzimir. 3,269,163 8/1966 Ripling et a1.

5 CHARLES W. LANHAM, Primary Examin r.

A. RUDERMAN, Assistant Examiner. 

